A wireless telecommunications system has been proposed with a central terminal, or station, at a central location in wireless communication with a plurality of subscriber terminals, or stations, at subscriber locations to implement a wireless telephony system. The system is intended to be used with fixed subscriber locations rather than the more familiar mobile cellular telephone systems.
The system finds a wide variety of possible applications, for example in rural, remote, or sparsely populated areas where the cost of laying permanent wire or optical networks would be too expensive, in heavily built-up areas where conventional wired systems are at full capacity or the cost of laying such systems would involve too much interruption to the existing infrastructure or be too expensive, and so on.
In the proposed system, the subscriber terminal is required to perform wireless transmission and reception tasks, signal coding and decoding tasks, initialisation and authentication tasks as well conventional telephony tasks. It will be appreciated that in order to ensure reliable communication with the central station, various line test procedures are needed.
Conventionally, each Subscriber Line Interface Circuit (SLIC) has had both a test-out and a test-in relay associated with it in order that a test circuit could be switched on-line when tests are to be performed on the cable or the SLIC. To provide multiple relays includes a significant cost element in the provision of the test facilities. The present invention is directed to providing an improved apparatus and method for telephone line testing.